(phixonline)--> with javascript_semantics constant queue = new_queue() printf(1,"empty:%t\n",queue_empty(queue)) push(queue,5) printf(1,"empty:%t\n",queue_empty(queue)) push(queue,6) printf(1,"pop:%v\n",pop(queue)) printf(1,"pop:%v\n",pop(queue)) printf(1,"empty:%t\n",queue_empty(queue))